1. Field of the Invention
The present invention relates to a light-emitting device and a method of fabricating the same, and more particularly, to a light-emitting device and a method of fabricating the same, in which the light emission characteristics of the light-emitting device in the ultraviolet (UV) range are maximized such that a high-efficiency light-emitting device can be produced at low cost.
2. Description of Related Art
Recently, light-emitting diodes (LEDs) have rapidly developed, to the extent that they are used in a variety of real-life applications. The usage of LEDs as a light source in displays or lighting systems continues to increase. Particularly, in LEDs that form a variety of light sources, an ultraviolet (UV) LED that emits light in the UV range is gaining interest as an important product in the lighting market.
However, gallium nitride (GaN), which is used as a semiconductor material for the UV LED, has a drawback in that its intensity is weak in the UV range. In order to compensate for this, GaN is used in the form of being alloyed with aluminum (Al).
In the meantime, some properties of zinc oxide (ZnO), such as a band gap and a crystal structure, are very similar to those of GaN. Therefore, ZnO is being actively studied as an inexpensive high-quality LED material that can replace GaN. In addition, unlike GaN, which is grown only on an expensive sapphire substrate, ZnO can be grown not only on a sapphire substrate but also on a glass substrate. Accordingly, the use of ZnO as an LED material can ensure price competitiveness.
Although the intensity of photoluminescence (PL) of ZnO is stronger than that of GaN in the UV range, this intensity is still not sufficient for actual application. Furthermore, when ZnO is grown on the glass substrate, its crystallinity is decreased, so its PL intensity in the UV range is necessarily decreased further.
Therefore, the development of a technology that can increase the PL intensity of ZnO in the UV range is urgently required so that ZnO can be used for the UV LED as a replacement to GaN.
The information disclosed in this Background of the Invention section is only for the enhancement of understanding of the background of the invention, and should not be taken as an acknowledgment or any form of suggestion that this information forms a prior art that would already be known to a person skilled in the art.